1.—Water is estimated, by drying the pulverized peat, at 212°, as long as any diminution of weight occurs. Well-dried peat-fuel should not contain more than 20 per cent. of water. On the other hand it cannot contain less than 15 per cent., except it has been artificially dried at a high temperature, or kept for a long time in a heated apartment.
2.—Ash is estimated by carefully burning the dry residue in 1. In first-rate fuel, it should amount to less than 3 per cent. If more than 8 per cent., the peat is thereby rendered of inferior quality, though peat is employed which contains considerably more.
3.—Sulphur and phosphorus are estimated by processes, which it would be useless to describe here. Only in case of vitriol peats is so much sulphur present, that it is recognizable by the suffocating fumes of sulphuric acid or of sulphurous acid, which escape in the burning. When peat is to be employed for iron manufacture, or under steam boilers, its phosphorus, and especially its sulphur, should be estimated, as they injure the quality of iron when their quantity exceeds a certain small amount, and have a destructive effect on grate-bars and boilers. For common uses it is unnecessary to regard these substances.
4.—The quantity of coal or coke yielded by peat, is determined by heating a weighed quantity of the peat to redness in an iron retort, or in a large platinum crucible, until gases cease to escape. The neck of the retort is corked, and when the vessel is cool, the coal is removed and weighed. In case a platinum crucible is employed, it should have a tight-fitting cover, and when gases cease to escape, the crucible is quickly cooled by placing it in cold water.
Coal, or coke, includes of course the ash of the peat. This, being variable, should be deducted, and the ash-free coal be considered in comparing fuels.
5.—The density of peat-fuel may be ascertained by cutting out a block that will admit of accurate measurement, calculating its cubic contents, and comparing its weight with that of an equal bulk of water. To avoid calculation, the block may be made accurately one or several cubic inches in dimensions and weighed. The cubic inch of water at 60° F., weighs 252-½ grains.
FOOTNOTES:
[10] The apparent specific gravity here means the weight of the mass,—the air-filled cavities and pores included—as compared with an equal bulk of water. The real specific gravity of the peat itself is always greater than that of water, and all kinds of peat will sink in water when they soak long enough, or are otherwise treated so that all air is removed.
[11] The "full" cubic foot implies a cubic foot having no cavities or waste space, such as exist in a pile, made up of numerous blocks. If a number of peat blocks be put into a box and shaken together, the empty space between the more or less irregular blocks, may amount to 46 per cent. of the whole; and when closely packed, the cavities amount to 30 per cent., according to the observations of Wasserzieher. (Dingler's Journal, Oct., 1864, p. 118.) Some confusion exists in the statements of writers in regard to this matter, and want of attention to it, has led to grave errors in estimating the weight of fuel.
[12] The waste space in peat and wood as commonly piled, is probably included here in the statement, and is usually about the same in both; viz.: not far from 40 per cent.